Portable electronic devices such as mobile telephones or personal digital assistants (PDAs) generally include a keypad for user input. Traditionally, the keypad is a set of physical keys or buttons that a user may push in order to make user selections. For instance, a cellular telephone may include a grid of physical keys or buttons that may be pushed in order to dial a phone number. However, in more recent portable electronic devices, the keypad is implemented as a virtual keypad displayed on a touch screen. The touch screen of the portable electronic device displays regions that may be touched by a user. The regions may be associated with digits 0-9, although other associations are possible (e.g., *, #, etc.). Selection of a region by a user results in the dialing of the corresponding digit in a phone number. The regions act as buttons or keys and generate a signal when touched. The signals generated are interpreted by the portable electronic device and result in the dialing of a phone number defined by the numbers associated with the touched regions.
Generally, a touch screen of a portable electronic device displays the virtual push button dial pad when the device is in a phone number dialing mode. In this mode, not only does the device display a dialing key pad, but the device also interprets user input through the dialing keypad in order to assemble and dial phone numbers. When the device is not in a phone number dialing mode, the virtual dial pad is not displayed and user input does not automatically result in the dialing of a phone number.
In many cases, the virtual dial pad displayed on a portable electronic device touch screen is similar in orientation and function to a standard touch tone telephone dialing pad. That is, the numbered buttons are arranged in four rows of keys, three columns wide. Numbers 0-9 are represented on the virtual “keys.” A “star” (“*”) key and a “pound” (“#”) key are usually also displayed. Other alpha-numeric symbols may also be associated with the virtual keys. Using this standard orientation, a user may dial a phone number by pushing the appropriate virtual keys. Thus, a user may dial a phone number using a touch screen of the portable electronic device in a way that is similar to most other touch tone dial pads function.